Both the AirPort Extreme wireless base station and the AirPort Time Capsule appliance, which is a combination of a base station and a 2TB/3TB wireless hard drive with built-in Time Machine support, have been pulled from Apple’s retail stores in the United States, an Apple support representative has confirmed to MacRumors.

Just three days ago, the AirPort devices received a rare firmware update.

“The base stations remain available to order online, while it appears the smaller AirPort Express can still be purchased both online and in stores at present time,” noted the publication. Authorized resellers still carry these devices.

Additionally, the Personal Pickup tool is no longer available on the AirPort Extreme and Time Capsule product pages on the US Apple Online Store.

A retail source told the publication that both the AirPort Extreme and Time Capsule remain in stock at Apple Store in the United Kingdom, Australia, Canada and Europe.

It wasn’t clear at post time why Apple’s wireless appliances were seeing in-store shortages in the United States. One viable explanation has it that Apple had to pull them because it’s required to comply with FCC’s June 2 deadline related to router software security rules which gradually phased in since 2014.

“Starting June 2, 2016, permissive changes will not be permitted for devices approved under the old rules, unless they meet the requirements of the new rules,” the FCC writes. “All devices partially or completely approved under the old rules cannot be marketed starting June 2, 2016 unless they meet the requirements of the new rules in all the bands of operation.”

Apple is holding its annual developers conference next month so it’s possible the company is prepping to update these devices with new hardware to enable the latest advances in Wi-Fi technology.

The newly released AirPort Base Station Firmware Update 7.6.7 fixed an issue which could prevent communication between clients on the same network, improved performance with an extended guest network and addressed potential naming conflicts with Bonjour Sleep Proxy.